what is the ideal commpresion ratio for a L20B street engine...what will give the best performance and with todays gas..say 92 octane???

i am geting forged pistons costom made so i need to know what commpression i'm looking at..

or lets say the highest commpression ratio i can run with 92 octane because i heard the higher the ratio the better

10-10.5:1 ...i'm running 11.5:1 on my L16 tho with 112 high octane fuel.

My L20B in the 720 is running at 10:1 and pings on unleaded in summer, thats 91RON I think. Whats wrong with running premium?

if its a street engine and you're planning on running regular ULP, don't waste your money on forged pistons. On this fuel a compression ratio around 9.5:1 would be to go. I'd definitely stay under 10:1 on regular ULP or you'll have problems with detonation/pinging.

so 10:1 will ping.....on 92 octane"super"..??

from 9:5:1 to 10:1 is there a difference in performance???if not i'll just go with 9:5:1

it depends on a few other factors, but yes on low octane LRP it would be best to keep compression down under 10:1. You can easily get this compression with cast replacement pistions and they will be more than up to the job. Spend the $800 dollars you save from the forgies on other stuff that will actually make it go harder.

the reason i'm going with the forged pistons is for the big cam i'm puting in...Lift=.592....the cast stock ones wont clear.....and i'm planning on running at least 150 shot nitrous...what do u think???

9.5:1 is the maximum you want to run on pump gas, well that's what I have been told, and thats what my A15 will be running at.

That kind of lift will pose difficulties with valves springs, and retainer to guide clearance I think.

if you're building such a serious engine, why are you only going to use horrible LRP fuel?

I have found that on fuel injected engines that premium ULP paid for itself in better economy & more power. I know this is because the computer alters the timing etc but surely there are similar benefits with careful tuning. I am particularly interested as I want to get the most of of my next engine & don't really want to compromise on fuel.